The present application relates to a network system in which sensor data obtained by individual mobile devices are shared on a network constructed in such a manner that the plurality of mobile devices each having a sensor function and a wireless communication function are arranged in a distributed manner, to a mobile device, to a method of controlling the mobile device, and to a computer program. More particularly, the present application relates to a network system in which each of a plurality of mobile devices operates in an autonomously distributed manner without using position information in a work space in order to form an ad hoc network topology, the obtained sensor data being shared, to a mobile device, to a method of controlling the mobile device, and to a computer program.
Still more particularly, the present application relates to a network system in which sensor data for a target found by an individual mobile device within a work space is shared among a plurality of mobile devices, to a mobile device, to a method of controlling the mobile device, and to a computer program. More particularly, the present application relates to a network system in which each of a plurality of mobile devices searches a work space, the mobile devices that have detected the same target perform tracking of the target, and sensor data for the target is shared among the mobile devices, to a mobile device, to a method of controlling the mobile device, and to a computer program.
Along with the rapid development of MEMS (Micro-Electromechanical Systems) technology in recent years, computers that are small, inexpensive, and have high performance comparable to that of supercomputers have been realized. It is expected that the widespread use of these types of computer systems will enrich the daily life of users.
As computer networks have become popular, information resource operations, such as sharing, distribution, and delivery of information, has been actively performed. As a result of the development of the Internet and broadband networks, convenience of information communication has markedly improved. Furthermore, as mobile units that can be connected to the Internet, such as PDAs and mobile phones, have become popular, a ubiquitous network or ubiquitous computing, which can be used anywhere and to which access from a global space is permitted, has attracted attention.
The configuration of computer systems has diversified. Examples of computer systems include typical computer systems including a display and a keyboard/mouse like a personal computer (PC), advanced computer systems having a user interface using speech recognition and image recognition, and robots that operate autonomously.
Unlike fixed computers, it is possible for a robot, in particular, to assist our activities by freely moving in a work space. Examples thereof include proxy handling of dangerous work and difficult work, such as maintenance work in a nuclear power plant, a thermal power plant, and a petrochemical plant, delivery and assembly work in a manufacturing factory, cleaning in a high-rise building, rescuing of people in a fire site and others.
Various kinds of sensors, including a camera, can be installed in a robot. Therefore, it is possible for a robot to obtain information (context) of the physical real world on the basis of sensor data while autonomously moving in a work space.
For example, by using a mobile robot having a sensor function and a wireless communication function as a sensor node and by arranging numerous sensor nodes in such a manner as to be distributed in a comparatively wide area, obtainment and distribution of information in the real world, such as obtainment of constantly changing environment information and simultaneous understanding of information over a wide area, can be performed. As a result of a plurality of mobile robots, each serving as a sensor node, autonomously moving in a coordinated manner and forming a network topology, an ad hoc or self-organized network, that is, a “mobile sensor network”, can be constructed.
The inventors of the present invention consider that, according to a mobile sensor network, new services that are not obtainable from a simple network in which sensor devices are connected or that are not obtainable from a single robot having a sensor function are made available.
However, at present, most sensor networks are of a type in which sensor nodes are required to be installed by a human being. In order to increase the efficiency of the topology, sensor nodes need to be installed while understanding the topology of the whole fields, and this is difficult. Several patent applications (for example, refer to Japanese Unexamined Patent Application Publication Nos. 2004-260526 and 2003-44974) have been filed regarding a sensor network system in which a topology is constructed statically and regarding a data collection system.
A method in which each sensor node includes moving means and a network topology is constructed dynamically has not yet attracted much attention in the field of network design. in the field of robotics, several research reports have been published in the past, but proposals in which specific applications are assumed are rare.
One application of a mobile robot having a sensor function includes searching for and tracking of a target. For example, a robot serving as a sensor node can be introduced in a disaster-stricken area so that victims can be found so as to be useful in rescue work. Alternatively, a mobile robot serving as a sensor node can be placed in unmanned premises at night so that searching for and tracking of a suspicious intruder can be performed.
For example, a method of capturing a still or moving target has been proposed (for example, refer to Japanese Unexamined Patent Application Publication No. 7-134031). However, in this method, since a target is captured and a map is created using position information obtained in advance, the method cannot be applied to a work environment where infrastructure has not yet been completed. The method is assumed to capture a target by a single robot as a target capturing device and is not related to a mobile sensor network in which a plurality of devices autonomously move in a coordinated manner, forming a network topology. Furthermore, it is considered that it is difficult to obtain information on a target on the basis of sensor data obtained from a single device.
Furthermore, a mobile robot that can autonomously return to a location where radio waves can reach after it has moved to a location where radio waves cannot reach and thereby continue operation has been proposed (for example, refer to Japanese Unexamined Patent Application Publication No. 2005-25516). However, this mobile robot is assumed to know, for example, the layout and the coordinate information of a building, and conditions in which radio waves can reach, of a radio-wave intensity map, and furthermore the robot is assumed to know its own position. In other words, this mobile robot cannot be applied to a work environment where infrastructure does not exist.
It is desirable to provide a network system, in which each of a plurality of mobile devices operates in an autonomous manner without using position information in a work space in order to form an ad hoc or self-organized network topology and the obtained sensor data is suitably shared, a mobile device, a method of controlling the mobile device, and a computer program.
It is desirable to provide a network system, in which sensor data for a target found by an individual mobile device in a work space can be shared, a mobile device, a method of controlling the mobile device, and a computer program.
It is desirable to provide a network system, in which each of a plurality of mobile devices searches a work space, and the mobile devices that have found the same target perform tracking of the target and can obtain sufficient information about the target, a mobile device, a method of controlling the mobile device, and a computer program.